EP1967482A1

EP1967482A1 - Window crane

Info

Publication number: EP1967482A1
Application number: EP08159179A
Authority: EP
Inventors: Jeffrey L. Crowder
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-06-29
Filing date: 2005-06-28
Publication date: 2008-09-10
Also published as: WO2006000808A3; GB0414476D0; CA2572045A1; GB2425521B; GB2425521A; EP1761454A2; WO2006000808A2; US20080035594A1; AU2005256855A1; GB2425521C; EP1761454B1; US7681747B2; DE602005019291D1; ATE457293T1

Abstract

A crane to be fitted in a window opening or the like, between two opposing surfaces, has a strut 14 which is first braced between the surfaces20a, 20b, and a boom 13 which extends away from the strut. A winch 5 on the crane winds up a lifting cable 12 which runs over pulleys 82, 84 on the boom 13. The top and bottom ends of the strut have end plates 15,7 which are designed to hold the crane rigidly between the two surfaces, but without damaging any surface finish on either surface. The winch is mounted on the strut so that when a load is fully lifted, further operation of the winch draws the boom towards the strut and towards the position of the operator.

Description

BACKGROUND

a. Field of the Invention

The present invention relates to a crane. More particularly, it concerns a crane suitable for assisting the installation of windows in a building.

b. Related Art

Windows are often fitted to a building by carrying them up a ladder, and then installing them whilst standing on the ladder. However, windows are heavy and working with ladders in this way inevitably puts the installers at significant risk. Alternatively, scaffolding may be used, but this is time consuming and costly to construct.

SUMMARY OF THE INVENTION

According to the invention, there is provided a crane for use in raising windows into place in a window opening in a building, the crane comprising an adjustable length strut having a head plate at one end and a foot plate at the other end and a boom mounted on the strut, the strut being extendable to press the head and foot plates against opposing surfaces of a window opening, wherein the boom is pivoted at one end to a lower region of the strut and wherein the crane includes a winch and a hoisting cable wound on the winch, the hoisting cable extending from the winch, around a pulley on the strut, over a pulley at a distal end of the boom and to a load engagement point, such that when a load is fully hoisted to the distal end of the boom, further winding of the winch draws the boom towards the strut.
The upper surfaces of the head plate and the lower surface of the foot plate preferably have engagement surfaces which will not mark the window opening, so that the crane can be used in a building without damaging any surfaces or decorative finishes which may have been applied. For example, the engagement surfaces can be provided with a rubber layer, which also helps to enhance friction between the plates and the surfaces of the window opening with which they are in contact.
The length of the strut can be adjusted so that the strut ends of the strut are in close contact with the top and bottom of a window opening. The strut can include a screw threaded member and a complementary threaded member engaged therewith, such that relative rotation of the two members varies the length of the strut. In a preferred configuration, the threaded member has an opening at one end which slidably receives an elongate member extending from the foot plate, and a pin is provided on the elongate member which extends through a slot in the threaded member, such that rotation of the complementary member about the screw threaded member urges it against the pin, which urges the engagement surfaces apart.
The length of the strut will depend on the distance between the surfaces against which the strut will be braced, and can be set, for example by the use of extension pieces, for specific applications.
The boom can preferably pivot about the axis of the strut through at least 90 degrees, so that a window supported on the crane can be lifted up the outside of a building with the boom projecting out at right angles to the plane of the window opening, and can then be manoeuvred into the window opening when the window is at the right height, by pivoting the boom into the plane of the window opening.
The crane may be configured so that in use the distal end of the boom is lower than the uppermost of the engagement surfaces. Thus the boom may be swung right into the opening in which the crane is mounted.
The length of the boom may be fixed, and the boom held at a predetermined angle in use which locates the distal end lower than the upper engagement surface. In another embodiment the angle of the boom may be adjusted to lower and raise the distal end as required. In a further embodiment, the length of the boom may be adjustable, by means of a telescopic boom section for example, which could also serve to vary the height of its distal end, enabling it to be brought within a window opening.
The boom can be pivoted at one end to the strut and, when in use, held at an angle to the strut by a flexible linkage between a distal end of the boom and an upper region of the strut. The boom can then be pivoted into a position where it is substantially parallel with the strut when it is not supporting a load. There may be a latch to hold the boom substantially parallel with the strut when it is not supporting a load.
When the window has been raised to the desired height, the boom can be pivoted about the axis of the strut to move the window into the window opening. The crane can remain in place, connected to the window, until the window is securely positioned in its final installation position. When pre-glazed windows are being installed, the crane can be attached to the window by suction pads attached to the window glass.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

Figure 1: shows a side view of a crane according to one embodiment of the invention;
Figure 2: illustrates the manner of operation of the crane of Figure 1;
Figure 3: shows a strut, with the boom not attached, illustrating possibilities for adjusting the length of the strut; and
Figure 4: shows alternative foot plate and head plate configurations.

DETAILED DESCRIPTION

Many details of the crane described here can also be shared with the details described in my patent application PCT/GB2005/002517 ( WO 2006/000808 ), and the reader is directed to that publication.
The crane has support means comprising an elongate strut 14, a head plate 15 and a foot plate 7. The crane is installed between two fixed surfaces provided by structures 20a and 20b shown in cross-section in Figure 3. Structures 20a and 20b define a window opening in a building, for example.
Figure 3 shows the construction of the strut 14. The strut has a main body 14a, with pivot axes at 50 for the boom 13 and at 52 for the hook 34. A long post 26a is mounted on the foot plate 7 and slides telescopically within the main body 14a. The post 26a has spaced holes 54, and a collar 14b at the bottom of the body 14a also has two spaced holes 56 (spacing different from that of the holes 54). Once the post 26a and the body 14a have been set to approximately the right length, a pin (not shown) is placed through one of the holes 56 and the nearest hole 54. The strut is then placed in the window opening and the threaded collar 32 is rotated to extend the threaded portion 30 until the strut is a tight fit between the structures 20a and 20b.
Figure 4 shows alternative designs for the foot plate and head plate, for use where the window opening is stepped with an upper structure 70a and a lower structure 70b. The head plate 60 here has a vertical surface 60b and a horizontal surface 60a. The corner between these surface portions is cut away so as not to interfere with ceiling decoration, exemplified by the coving 62. The foot plate 64 has a downturned flange 64 to fit over an edge on the lower structure 70b.
As can be seen from Figure 1, the winch 5 is mounted on the strut 14, and the cable 12 runs from the winch, over a pulley 80 at the top of the strut and then around two pulleys 82, 84 on the boom. Wires 11 are provided to limit the downward movement of the boom, but are omitted in Figure 2.
Figure 2 shows three different positions of the boom 13. In position A, the boom is at its lowest position (there will be suitable restraining equipment to stop it going any lower). The cable 12 as seen in this Figure is now shown with a stopper ball 86 a short distance above the hook 4. Once the stopper ball reaches the pulley 84, further winding up of the cable will bring the boom steadily upwards, through position B to position C, in which the load (hook 4) is practically in the window opening. Because the winch is mounted on the strut, winding up the cable 12 fully draws the boom up towards the strut.
The crane can be used to lift loads from and into the inside of a building by pivoting the boom through more than 90 degrees so that it extends inside the building. However in this position, the arrangement of head and foot plate will be less effective at maintaining the position of the strut between the top and bottom of the window opening, as the geometry of those components are designed to maintain the strut position when the load is suspended outside the building.
To avoid any possibility of the strut being dislodged from its normal position, when lifting or lowering loads inside the building, the crane will be provided with a latch to hold the boom up against the strut in position C. When the boom is fully raised, the latch will be engaged and will remain engaged when loads are being lifted or lowered inside the building, so that the forces acting on the strut will be substantially all up and down, and will not try to tip the strut over, into the interior of the building.
When the crane is in use, the boom is extended to the position shown in Figure 1 or the position A shown in Figure 2. It is held in that orientation by a tension wire or wires 11 which are attached between the axis of the pulley 84 near the distal end of the boom and a point 80 near the head plate end of the strut 14.
Means may be provided to adjust the length of the wires 11 to alter the angle of the boom 13 relative to the strut 14, for example to allow the boom to move to position A in Figure 2.
The strut is rotatable about its longitudinal axis relative to the foot and head plates, 7 and 15. Thrust bearings are provided in the strut/foot plate joint and at the strut/head plate joint to facilitates rotation of the boom 13 about this axis.
A hand operated winch 5 is mounted on the strut 14, having an elongate handle 36. A wire rope or cable 12 wound around the winch passes from the winch over a pulley 82 midway along the length of the boom and over a further pulley 84 at the distal end of the boom 13 and has a hook 4 at its free end. The hook can be replaced by any appropriate fitting to connect to an object to be lifted.
The crane is readily transportable with the boom in the retracted position C shown in Figure 2.
The boom is rotated around the longitudinal axis of the strut so that the cable 12 is suspended at a distance from the exterior of the building. The hook can then be lowered, and the winch used to raise the hook 4 once a load has been attached. The boom can be rotated again to bring the load horizontally towards the opening in which the crane is mounted.
The winch will have a conventional ratchet mechanism which can be engaged when lifting the load, to prevent the winch drum rotating in the opposite, unwinding, direction and disengaged when the cable has to be paid out.
As illustrated in Figures 1 and 2, the boom is held at an angle at which its distal end is lower than the upper engagement surface 22a.. It can therefore be swung within the window opening during the installation process.
The crane described herein can be configured to provide a substantial lifting capacity. An embodiment of the invention having a construction similar to that shown in the Figures has been found under test to have a lifting capability equivalent to four times that of two men (around 200kg). The distance between the engagement surfaces of the crane during this test was 800mm.
Preferably, in use, the crane is braced in the vertical orientation shown in Figures 1 and 2. Alternatively, a crane may be configured to be braced between engagement surfaces spaced apart in a horizontal or other direction. In a further variation, a crane may include two pairs of engagement surfaces, spaced apart in mutually perpendicular directions.
Although in the illustrated embodiment the engagement surfaces are urged apart using a screw thread arrangement, it will be appreciated that various other mechanisms may be used to achieve this. For example, a spring mechanism may be employed. Also the threaded configuration may instead be incorporated at another part of the support means, for example at the foot plate end of the strut.
The crane described here is highly portable. It can be quickly and easily mounted in an opening and can be easily moved around from place to place. It can be lightweight enough to be carried comfortably by one man and requires no special tools for its mounting in place, or its operation.
It will also be appreciated that the crane described herein may be used to suspend and/or raise and lower equipment other than a window from a building, for example a work platform.

Claims

A crane for use in raising loads, the crane being adapted to be secured in an opening in a building wall, the crane comprising an adjustable length strut having a head plate at one end and a foot plate at the other end and a boom mounted on the strut, the strut being extendable to press the head and foot plates against opposing surfaces of the opening, wherein the boom is pivoted at one end to a lower region of the strut and wherein the crane includes a winch on which a hoisting cable can be wound, the hoisting cable extending from the winch, around a pulley at an upper region of the strut, over a pulley at a distal end of the boom and to a load engagement point, such that when a load is fully hoisted to the distal end of the boom, further winding of the winch draws the boom towards the strut.
A crane as claimed in Claim 1, wherein the head plate has two faces substantially at right angles to one another for engagement with two surfaces of an edge of the opening in which the crane is to be used, and the foot plate having a toe edge extending rigidly at right angles to the axis of the strut.
A crane as claimed in Claim 1 or Claim 2, wherein the upper surfaces of the head plate and the lower surface of the foot plate have engagement surfaces which will not mark the edges of the opening.
A crane as claimed in Claim 3, wherein the engagement surfaces are provided with a rubber layer.
A crane as claimed in any preceding claim, wherein the boom can pivot about the axis of the strut through at least 90 degrees.
A crane as claimed in any preceding claim, wherein the boom is pivoted at one end to the strut and is held at an angle to the strut by a flexible linkage between a distal end of the boom and an upper region of the strut, so that the boom can be moved into a position where it is substantially parallel with the strut when it is not supporting a load.
A crane as claimed in Claim 6, including a latch to hold the boom substantially parallel with the strut when it is not supporting a load.